Quote Originally Posted by Vteckidd
Not true. I've seen stock hondas gain power open header. The whole question is "is his exhaust restrictive"

if it is it will gain power open header. If it's not then numbers won't be that different.

As far as damage or running lean, make sure you're on 93 octane and you'll be fine
going back to the 100 octane, will it run lean?